Reserve box/unbox/equals/hashCode methods inside inline classes

#KT-26573 Fixed

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java

@@ -330,6 +330,7 @@ public interface Errors {
     DiagnosticFactory0<PsiElement> INLINE_CLASS_CANNOT_IMPLEMENT_INTERFACE_BY_DELEGATION = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> INLINE_CLASS_CANNOT_EXTEND_CLASSES = DiagnosticFactory0.create(ERROR);
     DiagnosticFactory0<KtTypeReference> INLINE_CLASS_CANNOT_BE_RECURSIVE = DiagnosticFactory0.create(ERROR);
+    DiagnosticFactory1<PsiElement, String> RESERVED_MEMBER_INSIDE_INLINE_CLASS = DiagnosticFactory1.create(ERROR);
 
     // Secondary constructors
 

compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java

@@ -661,6 +661,7 @@ public class DefaultErrorMessages {
         MAP.put(INLINE_CLASS_CANNOT_IMPLEMENT_INTERFACE_BY_DELEGATION, "Inline class cannot implement an interface by delegation");
         MAP.put(INLINE_CLASS_CANNOT_EXTEND_CLASSES, "Inline class cannot extend classes");
         MAP.put(INLINE_CLASS_CANNOT_BE_RECURSIVE, "Inline class cannot be recursive");
+        MAP.put(RESERVED_MEMBER_INSIDE_INLINE_CLASS, "Member with the name ''{0}'' is reserved for future releases", STRING);
 
         MAP.put(VARIANCE_ON_TYPE_PARAMETER_NOT_ALLOWED, "Variance annotations are only allowed for type parameters of classes and interfaces");
         MAP.put(BOUND_ON_TYPE_ALIAS_PARAMETER_NOT_ALLOWED, "Bounds are not allowed on type alias parameters");

compiler/frontend/src/org/jetbrains/kotlin/resolve/TargetPlatform.kt

@@ -119,7 +119,8 @@ private val DEFAULT_DECLARATION_CHECKERS = listOf(
     SuspendOperatorsCheckers,
     InlineClassDeclarationChecker,
     PropertiesWithBackingFieldsInsideInlineClass(),
-    AnnotationClassTargetAndRetentionChecker()
+    AnnotationClassTargetAndRetentionChecker(),
+    ReservedMembersAndConstructsForInlineClass()
 )
 
 private val DEFAULT_CALL_CHECKERS = listOf(

compiler/frontend/src/org/jetbrains/kotlin/resolve/checkers/InlineClassDeclarationChecker.kt

@@ -139,4 +139,24 @@ class PropertiesWithBackingFieldsInsideInlineClass : DeclarationChecker {
             context.trace.report(Errors.DELEGATED_PROPERTY_INSIDE_INLINE_CLASS.on(it))
         }
     }
+}
+
+class ReservedMembersAndConstructsForInlineClass : DeclarationChecker {
+
+    companion object {
+        private val reservedFunctions = setOf("box", "unbox", "equals", "hashCode")
+    }
+
+    override fun check(declaration: KtDeclaration, descriptor: DeclarationDescriptor, context: DeclarationCheckerContext) {
+        val containingDeclaration = descriptor.containingDeclaration ?: return
+        if (!containingDeclaration.isInlineClass()) return
+
+        if (declaration is KtFunction && descriptor is FunctionDescriptor) {
+            val functionName = descriptor.name.asString()
+            if (functionName in reservedFunctions) {
+                val nameIdentifier = declaration.nameIdentifier ?: return
+                context.trace.report(Errors.RESERVED_MEMBER_INSIDE_INLINE_CLASS.on(nameIdentifier, functionName))
+            }
+        }
+    }
 }

compiler/testData/codegen/box/inlineClasses/inlineClassWithCustomEquals.kt

@@ -1,6 +1,8 @@
 // !LANGUAGE: +InlineClasses
 // IGNORE_BACKEND: JVM_IR
 
+@file:Suppress("RESERVED_MEMBER_INSIDE_INLINE_CLASS")
+
 inline class Z(val data: Int) {
     override fun equals(other: Any?): Boolean =
         other is Z &&

compiler/testData/diagnostics/tests/inlineClasses/reservedMembersAndConstructsInsideInlineClass.kt

@@ -0,0 +1,39 @@
+// !LANGUAGE: +InlineClasses
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+inline class IC1(val x: Any) {
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>box<!>() {}
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>box<!>(x: Any) {}
+
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>unbox<!>() {}
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>unbox<!>(x: Any) {}
+
+    override fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>equals<!>(other: Any?): Boolean = true
+    override fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>hashCode<!>(): Int = 0
+}
+
+inline class IC2(val x: Any) {
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>box<!>(x: Any) {}
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>box<!>(): Any = TODO()
+
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>unbox<!>(x: Any) {}
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>unbox<!>(): Any = TODO()
+
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>equals<!>(my: Any, other: Any): Boolean = true
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>hashCode<!>(a: Any): Int = 0
+}
+
+inline class IC3(val x: Any) {
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>box<!>(x: Any): Any = TODO()
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>unbox<!>(x: Any): Any = TODO()
+
+    fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>equals<!>(): Boolean = true
+}
+
+interface WithBox {
+    fun box(): String
+}
+
+inline class IC4(val s: String) : WithBox {
+    override fun <!RESERVED_MEMBER_INSIDE_INLINE_CLASS!>box<!>(): String = ""
+}

compiler/testData/diagnostics/tests/inlineClasses/reservedMembersAndConstructsInsideInlineClass.txt

@@ -0,0 +1,54 @@
+package
+
+public final inline class IC1 {
+    public constructor IC1(/*0*/ x: kotlin.Any)
+    public final val x: kotlin.Any
+    public final fun box(): kotlin.Unit
+    public final fun box(/*0*/ x: kotlin.Any): kotlin.Unit
+    public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+    public final fun unbox(): kotlin.Unit
+    public final fun unbox(/*0*/ x: kotlin.Any): kotlin.Unit
+}
+
+public final inline class IC2 {
+    public constructor IC2(/*0*/ x: kotlin.Any)
+    public final val x: kotlin.Any
+    public final fun box(): kotlin.Any
+    public final fun box(/*0*/ x: kotlin.Any): kotlin.Unit
+    public final fun equals(/*0*/ my: kotlin.Any, /*1*/ other: kotlin.Any): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public final fun hashCode(/*0*/ a: kotlin.Any): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+    public final fun unbox(): kotlin.Any
+    public final fun unbox(/*0*/ x: kotlin.Any): kotlin.Unit
+}
+
+public final inline class IC3 {
+    public constructor IC3(/*0*/ x: kotlin.Any)
+    public final val x: kotlin.Any
+    public final fun box(/*0*/ x: kotlin.Any): kotlin.Any
+    public final fun equals(): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+    public final fun unbox(/*0*/ x: kotlin.Any): kotlin.Any
+}
+
+public final inline class IC4 : WithBox {
+    public constructor IC4(/*0*/ s: kotlin.String)
+    public final val s: kotlin.String
+    public open override /*1*/ fun box(): kotlin.String
+    public open override /*1*/ /*synthesized*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*synthesized*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*synthesized*/ fun toString(): kotlin.String
+}
+
+public interface WithBox {
+    public abstract fun box(): kotlin.String
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -10947,6 +10947,11 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/recursiveInlineClasses.kt");
             }
 
+            @TestMetadata("reservedMembersAndConstructsInsideInlineClass.kt")
+            public void testReservedMembersAndConstructsInsideInlineClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/reservedMembersAndConstructsInsideInlineClass.kt");
+            }
+
             @TestMetadata("unsignedLiteralsWithoutArtifactOnClasspath.kt")
             public void testUnsignedLiteralsWithoutArtifactOnClasspath() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/unsignedLiteralsWithoutArtifactOnClasspath.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -10947,6 +10947,11 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/recursiveInlineClasses.kt");
             }
 
+            @TestMetadata("reservedMembersAndConstructsInsideInlineClass.kt")
+            public void testReservedMembersAndConstructsInsideInlineClass() throws Exception {
+                runTest("compiler/testData/diagnostics/tests/inlineClasses/reservedMembersAndConstructsInsideInlineClass.kt");
+            }
+
             @TestMetadata("unsignedLiteralsWithoutArtifactOnClasspath.kt")
             public void testUnsignedLiteralsWithoutArtifactOnClasspath() throws Exception {
                 runTest("compiler/testData/diagnostics/tests/inlineClasses/unsignedLiteralsWithoutArtifactOnClasspath.kt");

core/descriptors/src/org/jetbrains/kotlin/resolve/inlineClassesUtils.kt

@@ -57,4 +57,4 @@ fun PropertyDescriptor.isUnderlyingPropertyOfInlineClass(): Boolean {
     if (!containingDeclaration.isInlineClass()) return false
 
     return (containingDeclaration as ClassDescriptor).underlyingRepresentation()?.name == this.name
-}
+}